The new Mickey Mouse celebration cakes will be available to order beginning May 17th at Disney owned-and-operated sit-down restaurants.
The Mickey-shaped cakes are available in chocolate or white chocolate and can be customized with the messages “Happy Birthday” or “Congratulations”. The ears can also just be left blank. The cake serves 4 to 6 guests at a cost of $35 (plus tax and tip).
Pre-payment isn’t required, but reservations for the cake should be added to your existing dining reservation in advance, as day-of quantities are limited.
Source: Disney Parks Blog